sea troutDefinition of sea trout noun 1British a European brown trout of a salmon-like migratory race. Also called salmon trout.Salmo trutta trutta, family Salmonidae 2 [with modifier] North American a trout-like marine fish of the drum family occurring in the western Atlantic. Genus Cynoscion, family Sciaenidae: several species, including the weakfish sea trout in other Oxford dictionaries Definition of sea trout in the US English dictionary